bug#15011: 24.3; Scrolling Performance

[Eli Zaretskii]

> Date: Fri, 2 Aug 2013 16:21:38 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> 
> > Scrolling is known to be slow in C++ files without some performance
> > tunes. I use these two customizations myself:
> > 
> >  '(font-lock-maximum-decoration (quote ((c++-mode . 2))))
> >  '(jit-lock-defer-time 0.01)
> 
> Should settings such as these be turned on by default in C++ mode?

The 2nd one causes fast scrolling (e.g., lean on the "C-v" key)
refrain from fontification, so you see unfontified text scrolling past
you.  Therefore, I'd advise against such default.